Experimental Investigation Of Regenerators Under Oscillatory Flow

Regenerator, as a heart in stirling or thermoacoustic-stirling, is a crucial aspect for improving stirling's efficiency. With the progressing of todays'stirling or thermoacoustic-stirling, more deep understanding of nature of regenerator is a newly academic opinion. The previous experimental results and correlative formulas, both basing on steady flow condition, are not enough to predict realistic situation. In fact, regenerator is used under oscillatory flow and characteristics of flow and heat transfer in regenerator matrix are different from those under steady flow. Especially, when regenerator is used under higher oscillatory frequency, experimental result deviation is more obvious under steady flow than under oscillatory flow.This work is intent to design test rigs and perform experimental investigation on characteristics of flow, heat transfer and acoustic power conversion in regenerator under oscillatory flow. In the beginning, a dynamic pressure drop test rig, which simulated the realistic working condition that regenerator worked, was designed to investigate regenerator pressure drop characteristics under oscillatory flow. Furthermore, some valuable results, from regenerator with different porosity, different packed length, different packed pattern and temperature difference was given. Much effort was also employed to tentatively study axial thermal conduction and net axial energy flux in the regenerator. The experimental results demonstrated that the dynamic pressure drop of screen type regenerator is linearly related to the porosity and the length of regenerator, but is not obviously correlative to the packed pattern of regenerator under other conditions unchanged; Besides, the dynamic pressure drop of regenerator increases with the temperature difference across the regenerator, however, it has no obvious relation with the orientation of temperature change.Also, basing on the fact that thermoacoustic-stirling performance is effected to a large extent by thermoacoustic characteristics of regenerator, a thermoacoustic-stirling acoustic power amplifier was designed with the aim at understanding the acoustic power amplification and frequency-choice characteristics of regenerator.Besides, some sensors and instruments used in experimental work are carefully introduced. Some auxiliary experimental rig was also developed for calibration of sensors and instruments and the calibration tips and operation procedure were supplied as well.